Lamp



LAMP

Filed Jan. 25, 1932 Patented on. 27, 1936 UNITED STATES.-

a George Sperti, Govington, Ky aasignor to Sperti Lamp Corporation, NewYork, N. Y., a corporation oi. Delaware Application Januaryflfi, 1932,Serial No. 588,749

6 Claims. (01. ire-1) This invention relates to lamps of the typecombining a source of visible radiation such as an incandescent filamentwith an arc constituting a source of visible and ultra-violet radiationand 5 particularly to an arc element for use in such or other lamps orfor use as an arc lamp alone.

, In prior applications of George Sperti, forexample, applicationSerial. No. 572,394, filed October 31, 1931, there are disclosed lampsof the k above type wherein the source of visible radiation isconstituted by an incandescent filament of tungsten or the likeandwherein the are is established between electrodes in an atmosphere ofionized gas or vapor'such as mercury. 'The resultant spectrum of such alamp is that of the incandescent filament having superimposed thereonthev spectrum of the arc, so that the radiation from the lamp closelyresembles natural sunlight in character and quality. The are radiationreinforces the radiation from the incandescent filament particularly inthe short ultra-violet which is of recognized therapeutic value, andmeans are provided for preventing the emission from the lamp ofobjectionable radiations shorter than about 28m) to 2900 Angstrom units.

Lamps .of this type are designed iorgeneral illumination so as toprovide artificial light equivalent or nearly equivalent to naturalsunlight and to this end they should be capable of use in place or theordinary incandescent lamp at normallighting. voltages and currents. Thelampdescribed in the aforesaid application embodies both an outer and aninner bulb, the incandescent filament being disposed in the outer bulband the arc in the inner bulb so that these two sources may be operatedindependently as regards conditions such as gas and vapor pressure, etc.Hence the arc element is complete in itself and M may, if desired, beused without the incandescent filament seen are lamp. The design of thelamp described above,.however, is such that it may be. used to replacethe ordinary incandescent lamp for all purposes without the use ofexterm nal controlling and starting devices, ballasts, etc. The lampdisclosed in the aforesaid application is particularly adapted for usewith alternating currents, although also operable with direct ourrent,and the object of the present invention is to provide a novel lamp ofthe type described and more particularly a novel are element for usealone or in such a. lamp which is particularly adapted for use withdirect current, although it may also be used with alternating current.

5 One embodiment oi the invention has been acteristics.

illustrated in the accompanying drawing,- but it is to be expresslyunderstood that said drawing is for purposes of illustration only and isnot to be construed asa definition of the limits of.

the invention, reference being had to the appended claims for thispurpose.v

In the drawing, Fig. l is a perspective view of a lamp embody-. ing theinvention; and

Fig.2 is a sectional view of a part oi the lamp 10 shown in Fig. 1.

- Referring new toy the drawing, the lamp in the form shown comprisesabulb l of any desired type, size and shape which is mounted in theusual or anysuitable base 2. In the form 15 shown, the bulb l isconstituted of material which transmits ultra-violet light of thedesired wave lengths, that is, ultra-violet radiationslonger than 2800to 2900-Angstrorn units. Thebulb may, if desired, be of material whichis opaque m; to shorter radiations, but in the form shown it isunnecessary that this bulb have filtering char Sealed in the neck of thebulb'is a, stem or standard 3 constituting the usual means forintroducing conductors t and 5 into the bulb as and forsupporting thevarious elements within the bulb. An incandescent filament t, ortungsten or other suitable material, is supported in v the bulb l bymeans of wires l and t that are fused in the stem 3, the wire Iconstituting a. no.

connection from one end of the filament tothe conductor t. Filament 6may also be supported by a plurality of wires 9 carried by a bead itformed on an inner bulb H which is in turn supported from the stem 3 bymeans or a-supat porting. band it and supports it and M1. In

. most cases, it is desirable that the bulb ll have i or standard it andpreferably contains a-quantity of mercury or other ionizable gas orvapor which produces the desired radiations. Enclosed within the bulb His a pair of cold electrodes be-- to tween which the arc is established.In order to render the lamp self starting, at least one of theseelectrodes is associated with an ionizing element which is adapted to beheated so as to assist in ionizing the gas or vapor within the bulb andin starting the arc. Referring now to Fig. 2: one

- of the electrodes comprises a grid or coil 21 carried by asupporting'wire 26, said coil surrounding and being electricallyconnected to a heated ionizing element which in the form shown comprisesa tube [6, preferablyvclosed at one 'end, supported in the inner bulb Hin any suitable manner as by means of a supporting band I1 and.

a supporting wire l8 that is fused in the stem IS. The tube l6 may be ofmetal such as nickel or tungsten, or of conductive oxides such aszirconium oxide, etc. lreferably the tube is coated either partially orentirely with one or more oxides which have relatively high electronicemission when heated, such as oxides of barium, strontium, thorium,etc., this coating being indicated diagrammatically at Is. Where thetube i6 is made of zirconium oxide and the like, one or more of theseactive oxides may be mixed with the zirconium oxide.

The other electrode is constituted by a substantially cylindricalelement surrounding the electrode 21 and supported in any suitablemanner as by means of wires 2i and 22 that are fused in the standard I5.In the iorm shown, said element 2!! comprises a wire screen, but .it maybe a cylindrical plate or coil.

A potential difierence is established between the electrodes 21 and 20in any suitable manner, preferably by connecting in parallel with saidelectrodes a circuit which includes means for heating the ionizingelement l6. As shown, one end of the'filament 6 is connected to the wire8, and the aforesaid parallel circuit is connected between the wire 8and theconductor 5. To this end a wire 23 is connected to the supportingwire 8 and also to the support 2|. connected at one end to the electrodesupport 2| and at the other end to a heating filament 25 enclosed withinthe ionizing element IS. The other end of filament 25 is connected bothto the tube support It and to the supporting wire 26 which carries coilelectrode 21 surrounding the tube l6. Filament 25 may be insulated fromthe, tube IS in any suitable manner as by coating said filament with asuitable cement? When'current is supplied to the lamp, it first fiows'inseries through the conductor 4, supporting wire 1, filament 6,supporting wire 8, wire 23, resistance 24, filament 25, wire 26 andconductor 5. It will be noted that the electrodes 20 and 21 are.connected across or in parallel with the resistance 24 and the filament25 so that the potential drop therethrough is impressed across saidelectrodes to establish and maintain the arc therebetween. The are maystrike at once between the electrodes 20 and 21, in which case the tubeis will practically remain unheated because the resistance 25, 24 isgreater than the resistance of the parallel arc path. If the arc failstostrike, the filament 25 heats the tube I6 and also supplies heat tothe atmosphere of gas or vapor within the bulb l I. The heating of tubeI 6 drives 01! any ions of gas or vapor which were adsorbed by said tubeand also heats the oxide coating l3 so that the electronic emissionthere- A resistance 24 is rapid disintegration by this cooling oiI ofthe filament 25 and, also by the protection against electronicbombardment afiorded by the grid electrode 21. I

The electrode 21 should be negative with respect to the electrode 20' inorder for the arc to operate properly in case direct current is used.This can be insured by proper wiring of the sockets in which the lampis' used, or if desired,

included in the wiring connections to the socket so that if the arc doesnot start the polarities of the socket terminals may be reversed.Referring to Figure 1, a suitable socket is shown at 28, current beingsupplied to the socket by wires 28 and 30 which lead to the poles 3i and32 of a reversing switch 33 of any suitable type. In case the lamp doesnot start when the switch 33 is closed, said switch is reversed in orderto reverse the polarity of the electrodes 21 and 20. It will beunderstood that the reversing switch is illus trated in diagrammaticform only; for example, it may comprise either a rotary switch or aknife switch and may have any suitable structural relationship with thesmket 28. i

(It will be understood that the invention is not limited to the formdescribed and illustrated in.

the drawing. Thus the bulb I may have any desired shape and size and maybe mounted in any desired type of base. Similarly the bulb ll may haveany desired size and shape and may be supported within the lamp in anysuitable manner The ionizing element l6 may be of different materials asdescribed above and may be of other forms than tubular. The gridelectrodes 21 may also comprise a screen or the like within the lamp mayalso be varied. For example, the resistance'24 may be constituted by aportion of the filament 8 by suitable connections which will be apparentto those skilled in the art, and in some cases the resistances of thefilament 25 will be suflicient without the use of additional resistancessuch as resistance 24. may be made in the form, details of constructionand arrangement of the parts without departing from the spirit of theinvention and reference is therefore to be had to the appended claimsfora definition of the limits oi the invention.

What is claimed is:

1. An electric arc lamp comprising three concentric tubular elements,the inner element comprising an oxide coated member having highelectronic emission when heated and the intermediate and outer elementscomprising cold electrodes, a connection between the inner andintermediate elements placing said elements at substantially the samepotentialwith respect to the circuit of the lamp, 9. singlepair of lampterminals, connections from said terminals to the in-' termediate andouter elements, and resistance means connected between said terminalsand including a heating fllamerit within said inner element and inparallel with said intermediat and outer elements.

- 2. An electric arclamp comprising a tubular ionizing element coatedwith an oxide having high electronic emission when heated, a singlepairof lamp terminals, a heating filament connected between-saidterminals and disposed with-. in said ionizing element, a cold electrodeadjacent a reversing switch of any suitable type may be Otherchangesinstead of a coil. The electrical connections said'ionizingelement and connected therewith, a

, second cold electrode spaced from said first electrode and ionizingelement, and connections from .saidelectrodes to said terminals.

3. An electric lamp comprising a bulb, an incandescent filament therein,an inner bulb, a tubular ionizing element coated with an electronemissive material disposed within said inner bulb,

a cold electrode associated with said ionizing element, a second coldelectrode in said inner bulb spaced from said first electrode,resistance means including a heating filament and connected in serieswith said incandescent filament across the terminals of the lamp, saidheating filament being disposed within said tubular ionizing element,and connections from said electrodes to said series circuit at points ofdifierent potential. v

4. An electric arc lamp comprising a bulb, a pair of cold electrodes insaid bulb, a single pair of terminals for said lamp, connections betweensaid terminals and said electrodes, an electronemi'ssive ionizingelement in said bulb, and resistsmce means including a. heating filamentfor said ionizing element connected between said electrodes in parallelwith the arc path therebetw'een.

5. An electric arc lamp comprising a bulb, .a

pair of concentric-cold electrodes in said bulb, a single pair ofterminals for said lamp, connections between said terminals and saidelectrodes, on electron-emissive ionizing element adjacent to ,andelectrically connected with one of said electrodes, and resistance meansincluding a heating filament for said ionizing element connected betweensaid electrodes in parallel with the arc path therebetween. ,1

6. An electric lamp comprising-an outer bulb, an incandescent filamentin said outer bulb, an inner bulb, a pair oi cold electrodes in saidinner bulb, a single pair of terminals for said lamp, said incandescentfilament and electrodes being connected in series across said terminals,an electron-emissive ionizing element in said inner bulb, and resistancemeans including a heating filament for said ionizing element connectedbetween said electrodes in parallel with the arc path therebetween.

' GEORGE SPERTI.

